From f464b7aee92893622c53210638b7d2e8f754e106 Mon Sep 17 00:00:00 2001 From: Saurabh Sengar Date: Thu, 29 Aug 2024 12:43:11 +0530 Subject: [PATCH] uio_hv_generic: Fix kernel NULL pointer dereference in hv_uio_rescind commit fb1adbd7e50f3d2de56d0a2bb0700e2e819a329e upstream. For primary VM Bus channels, primary_channel pointer is always NULL. This pointer is valid only for the secondary channels. Also, rescind callback is meant for primary channels only. Fix NULL pointer dereference by retrieving the device_obj from the parent for the primary channel. This fixes CVE-2024-46739 Cc: stable@vger.kernel.org Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support") Signed-off-by: Saurabh Sengar Signed-off-by: Naman Jain Link: https://lore.kernel.org/r/20240829071312.1595-2-namjain@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Huang Cun Signed-off-by: Jianping Liu --- drivers/uio/uio_hv_generic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index bdf3932ee3f2..4a4a809f8410 100644 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -104,10 +104,11 @@ static void hv_uio_channel_cb(void *context) /* * Callback from vmbus_event when channel is rescinded. + * It is meant for rescind of primary channels only. */ static void hv_uio_rescind(struct vmbus_channel *channel) { - struct hv_device *hv_dev = channel->primary_channel->device_obj; + struct hv_device *hv_dev = channel->device_obj; struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); /*